For example, a straddle-type vehicle includes an exhaust device which cleans an exhaust gas emitted from an engine in such a manner that a catalyst is caused to contact the exhaust gas. In the straddle-type vehicle, to reduce an exhaust noise radiated from the engine by efficiently utilizing a limited space, a muffling space is formed inside the exhaust device, in some cases. By securing this muffling space, the straddle-type vehicle can effectively reduce the exhaust noise radiated from the engine.
For example, as disclosed in Patent Literature 1, in some cases, the straddle-type vehicle is provided with an oxygen sensor for detecting an oxygen concentration of the exhaust gas, at a location that is upstream of the catalyst of the exhaust device, in a flow direction of the exhaust gas.